Tech 2

[iwaslowr]

Does anyone have access to one? After installing my wheels the increased PSI is causing the DIC to prompt a "check tire pressure" message for each tire at each ignition cycle...

 

[Sepiroth]

I doubt it is due to the larger wheel. What it reads like is that maybe one or more of the pressure sensors arent communicating the correct air pressure.

 

[JennaBear]

Did your shop do the proper calibration on the TPSs?

 

[iwaslowr]

The wheels and tires were shipped to me mounted/balanced, etc. so all I had to do was install them. Thereafter the re-learn of the sensors was successful but now the ECM is prompting the DIC to display the "check tire pressure" message because 45-50 PSI is much to high for a stock tire/wheel application....

 

[JennaBear]

Maybe I am reading this wrong, so the person that shipped them to you had the sensors already installed in them?

 

[iwaslowr]

Maybe I am reading this wrong, so the person that shipped them to you had the sensors already installed in them?

Correct, the TPMS were included.

 

[CodeB4U]

I have access to a Tech 2, What sensors did the shipper install? Part #'s? How did you relearn the TPM? Does it give a TP reading? What are they?

 

[JennaBear]

Correct, the TPMS were included.

That just might be your problem.

 

[iwaslowr]

I have access to a Tech 2, What sensors did the shipper install? Part #'s?

I am not sure what sensors they were... but can find out tomorrow if this is necessary.

How did you relearn the TPM? Does it give a TP reading? What are they?

I followed the Owner's manual re-learn process which was successful. They all give accurate TP readings which is currently ~ 46 PSI cold.

 

[quikag]

46psi cold is WAY too high. Lower to 32/33 cold and you should be fine.

 

[CodeB4U]

I am not sure what sensors they were... but can find out tomorrow if this is necessary. Not necessary right now, but yes there are different TPM with different limits. You have to match them to the correct tire pressure you are going to be using. example: some sensors don't register tire pressures above 42 PSI. But if it's reading 46 then obviously your TPM is the correct one.



I followed the Owner's manual re-learn process which was successful. They all give accurate TP readings which is currently ~ 46 PSI cold.So you deflated or inflated the tires I'm guessing? You don't have the scan tool right?

Another problem could be is, if you had factory 20" your tire pressure should be 30-32 depending on the yr of your hoe, your BCM is programmed to 30-32 PSI sensors, so for you having your tire pressure at 46 it's over inflated according to your BCM because that's what it's programmed to read. All you did when you re-learned your tires is where that sensor is located...like RR or FR or LF etc etc...you didn't program the BCM to say, i want 46 PSI to be normal PSI. So what i do when customer's come in with the same problem is find out the pressure the tires are suppose to be or to the customers specs and then go in with the tech 2 and change the normal 30psi to be at whatever psi it should be. Then your BCM will know...ok 46 PSI at LF check, 46 at RF check, 46 @ RR check, 46 @ LR check and then is when your light will go away.

46psi cold is WAY too high. Lower to 32/33 cold and you should be fine.

Not necessarily, the lower/thinner the sideway...like a 30 series tire need more PSI at a colder temp. Low PSI in a thin walled tires=cracked rims when going over pot holes. VS like a rock crawler tire which has a LARGE sidewall and are ran at 5-15 PSI to conform to the terrain or rocks for better grip. Hence needing beadlockers because with that little PSI the rim would just spin in the tire or just shot out the little air it has on a little bump.

 

[preston]

From what I remember, there is no way to reprogram the computer to change the psi range for the tires/tpms. You will either have to deal with the message every time you start the vehicle or lower your psi a little bit. I set my psi at 40psi cold too avoid the message.

 

[Timmy]

wow. that's alot of air

 

[iwaslowr]

46psi cold is WAY too high. Lower to 32/33 cold and you should be fine.

The tires I chose, Pirelli Scorpion Zero Asimmetrico 305/30/26, have a maximum of 50 PSI... and once they heat up that pressure is reached. I'm sure they can be ran at a lower pressure, but it's not worth the risk of bending a rim (been there, done that - too many times). Ride quality is not quite as spongey as the stock 17's but is very tolerable considering the sidewall, or lack thereof, with the 26's.

So you deflated or inflated the tires I'm guessing? You don't have the scan tool right?

I do not have the scan tool and only followed the owner's manual for the re-learn process by deflating each tire based on the instructions.

 

[CodeB4U]

I do not have the scan tool and only followed the owner's manual for the re-learn process by deflating each tire based on the instructions.

Well all it would have done with the scan tool was make thing's alot faster, but it still did the position sensors the correct way. Just take it to the dealership and have them program the BCM to a higher PSI warning.

 

[iwaslowr]

Well all it would have done with the scan tool was make thing's alot faster, but it still did the position sensors the correct way. Just take it to the dealership and have them program the BCM to a higher PSI warning.

Thanks CodeB4U! Do you happen to know if this higher PSI data will be overwritten with an aftermarket tune?

 

[05Yukon]

Shouldn't be its not in the PCM.

 

[CodeB4U]

Shouldn't be its not in the PCM.

No, if you get real technical it's neither the PCM or the BCM. It's the RCDLR module. But i inserted BCM to keep the technicality down and not confuse the minds of who are not familiar with the terms.

PCM Powertrain Control Module
BCM Body Control Module
RCDLR Remote Control Door Lock Receiver (located on the driver side rear pillar by the speaker.)

 

[jwtahoe]

Had the same prob. Serv. Tech. Put 30 psi 295/35/24 all is well

 

[allando]

Yeah, if I remember, you can only program tire size up to ***/**/22 on the tech II... As for the tire pressure, it can be set for higher pressures. I did it to mine. I don't think it's the same process as learning the TPMS. Gotta have someone w/ a tech II play around w/ it. It's been awhile since I last used a tech II for TPMS haha.